Tuberculosis: are we barking up the wrong tree?

Lead Research Organisation: Liverpool School of Tropical Medicine
Department Name: Clinical Sciences


Tuberculosis causes more than 10 million cases each year and its control is based on identifying smear-positive patients who are consider the main source of transmission in the community. This project aims to challenge this basic premise.

Recently, baseline studies in South Africa reported that about 10% of apparently healthy adolescents being evaluated to participate in vaccine trials had asymptomatic tuberculosis infection in the oropharynx (confirmed by culture). Most recently, a cohort of adults with confirmed TB were shown to have M. tuberculosis infection in the mouth gum, and that a proportion of asymptomatic contacts in the household also carry the infection in their gums. We have also found that the same is true for patients in Moldova. These - unpublished - studies of asymptomatic infections with M. tuberculosis and carriage of the bacteria in the mouth suggest that transmission of TB and carriage may play a role in the epidemiology of TB. You would challenge conventional wisdom and explore:

How frequent is asymptomatic carriage among key populations, specifically among adults and children in contact with adults with pulmonary TB and population groups in congregates (prisons, markets, religious centres).

The natural course of asymptomatic carriage, and proportion of individuals progressing to TB.

Whether asymptomatic infections elicit immunological responses

Performance of diagnostic test in clinical samples obtained from asymptomatic carriers

Develop models of the potential for disease transmission based on your study findings

Conduct systematic reviews of asymptomatic carriage of other zoonotic mycobacteria.


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